// Copyright (c) 2009-2010, Jeremy Brewer
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

package galaxie500.numeric;

import galaxie500.collections.DoubleList;

/**
 * Decorator function which stores all x values passed to valueAt() and the
 * function values computed there and returns the value of the decorated
 * function unaltered.
 * 
 * @author Jeremy Brewer
 */
public class ValueStoringFunction implements Function {
  private Function f;
  private DoubleList xValues;
  private DoubleList fValues;

  public ValueStoringFunction(Function f) {
    this(f, 1000);
  }

  public ValueStoringFunction(Function f, int initialCapacity) {
    this.f = f;
    this.xValues = new DoubleList(initialCapacity);
    this.fValues = new DoubleList(initialCapacity);
  }

  public double valueAt(double x) {
    double fValue = f.valueAt(x);
    xValues.add(x);
    fValues.add(fValue);
    return fValue;
  }
  
  /**
   * @return A list of all of the x values where valueAt has been invoked
   */
  public DoubleList xValues() {
    return xValues;
  }

  /**
   * @return A list of all of the values of f(x) where valueAt has been invoked
   */
  public DoubleList fValues() {
    return fValues;
  }
}
